With advancement of lawn mower technology over the recent years, it has now become established that misalignment of the rotating lawn mower cutting blade relative to its horizontal plane of operation and its associated blade housing can seriously effect the performance of the mower. Misalignment of the cutting blade or its mounting to the associated mower housing can cause harmful contact between the extremities of the blade and the associated blade housing. This not only causes harmful wear on the parts and impairment of the blade speed and cutting operation but also it can adversely effect the flow of the cut grass clippings in the blade housing to cause clogging and stalling of the blade in some instances.
The need for an accurately aligned cutting blade operating within predetermined tolerances with respect to its associated housing becomes even more important when used with mowers which produce a high vacuum within the blade housing for facilitating the cutting of grass and the movement of the grass clippings out of the housing.